The New Zealand Warriors' getaway to Perth coincided with Andrew McFadden's two-month anniversary as head coach, and although the honeymoon isn't over, a gift-wrapped victory for South Sydney showed signs of a communication breakdown.

Far from using the NRL's longest road trip as an excuse once another second-half capitulation at nib Stadium culminated in a 34-18 defeat - or a kickoff time that saw most of the Rabbitohs' damage inflicted in the early hours of yesterday - McFadden was instead critical of his players after they failed to prey on an injury-depleted opponent.

The phrase "missed opportunity" will be associated with this performance - and a careless second half may return to haunt the Warriors should they fail to make the finals series.

Leading 10-6 at the break after absorbing massive defensive pressure - and aware Kangaroos and Queensland star Greg Inglis would not return from an Origin-threatening ankle injury - the Warriors should have been set up for a historic win in Western Australia after five forlorn excursions.

Five-eighth John Sutton and man-of-the-match Dylan Walker also played though the pain barrier to mastermind the recovery while the Warriors emerged unscathed, apart from some serious self-inflicted damage.

McFadden, who has a four-win, four-loss record since replacing Matt Elliott, was in no mood to offer mitigating factors despite the Warriors' third successive fade out in Perth.

"The travel hasn't been a factor, we were well prepared," said McFadden, of a flight plan that had the squad arriving in WA on Wednesday to acclimatise.

"We just went away from what we've been practising. It was very disappointing given the circumstances surrounding the opposition - they were cherry ripe for the picking.

"Early in that second half and we're looking like we're on top, but we made too many errors and just lacked concentration."

The inability to capitalise on Shaun Johnson's 40-20 kick soon after Mannering crossed summed up the Warriors' shoddy second half as South Sydney thrived under adversity.

"The stuff we were doing out there, I didn't recognise," said McFadden, who was unable to refocus a team despite frequent messages to tighten up.

The Warriors committed twice as many errors as South Sydney while their resolute defensive effort in the first-half deteriorated dramatically.

Walker and Kyle Turner signalled the momentum shift before prop David Tyrrell scored a brace and Joel Reddy soared unchallenged to touchdown a cross kick.

"The way the tries were scored, that hasn't been us for the last month. They were soft tries," said McFadden, who was still confident the team would redeem themselves when they host Brisbane at Mt Smart on June 21.